In various diseases, such as diabetes and hyperlipidemia, management of biological components in blood, such as blood glucose (blood sugar) and blood cholesterol, is important to prevent and treat the diseases. However, to measure biological components in blood, a small amount of blood usually needs to be drawn, which is painful. And troublesome operations, such as sterilization of a blood drawing area and proper treatment of consumables, are necessary, so that, frequent blood drawing for the measurement of biological components for preventive purposes, for example, is apt to be averted.
Consequently, non-invasive measurement devices that measure biological components without drawing blood are proposed. As an example of the devices, Patent Literature 1 describes a method, wherein light is cast to a biological tested area, and as a result, biological components are detected using spectral characteristics of light (object light) emitted from biological components in the tested area.
In the method described in Patent Literature 1, an interference using an object beam generated from each bright point that optically forms the biological components is used to acquire an interferogram of the biological components, and the interferogram is Fourier-transformed to obtain spectral characteristics (spectrum) of the object light. Specifically, object light, including transmitted light and diffused/scattered light, generated from each bright point is introduced through an objective lens to a phase shifter composed of a fixed mirror unit and a movable mirror unit, and object beams reflected from the two mirror units interfere with each other on an imaging plane. The movable mirror unit is moved by a piezo element or the like, and a phase shift according to the moving distance of the movable mirror unit is given to the object beams reflected from the fixed mirror unit and the movable mirror unit. Accordingly, the intensity of the interference light is changed, and a so-called interferogram is acquired. The interferogram is Fourier-transformed to obtain the spectral characteristics (spectrum) of the object light.